Television system



TELEVIS ION SYSTEM Filed June 12, 1930 2 Sheets-Sheet 1 I J I I J I ,I J l 1I= S r J J J c J C l I j I 2 J L J c Q l r F A Q J 1 I g g 46 I I 45 INVENTOR.

. 86mm QfQwi a,

A TTORNE Feb. 7, 1933.

C. L. DAVIS.

TELEVISION SYSTEM Filed June 12, 19.30

2 Sh'eeiLs-Sheet 2 INVEN TOR. swam $1. Dow/1o,

' 9 0%,! O ATTORN Y Patented Feb. 7, 1933 UNITED STATES PATENT OFFICE CHESTER L. DAVIS, OF K EOK'UK, IOWA, ASBIGNOB '10 WIRED RADIO, INC, NEW YORK, N. Y A CORPORATION 01 DELAWARE TELEVISION SYSTEM Application filed June 12, 1980. Serial No. 480,700.

provide a system for scanning an ob'ect at a television transmitter under the e ects of different color screens which are shifted inv timed relation to the variation in frequency of the signaling energy with means at a receiver responsive to the signaling energy over a variable frequency range and responsive to the effects produced by the different color screens through which the object is scanned at the transmitter.

A further object of my invention is to provide a system for. television having circuits arranged at a transmitter and receiver for the transmission and reception of signaling energy over a variable frequency range for shifting a potential node along a screen under control of the variable signal transmitted over a variable frequency range depending upon the effects of scanning an r object through diiferent color filters.

Other and further objects of my invention reside in an arrangement of circuits for the transmission and reception of color television signals as set forth more fully in 9 the specification hereinafter following by reference to the accompanying drawings, in which:

Figure 1 diagrammatically illustrates the arrangement of color screens at the television receiver for viewing the reproduced image in color; Fig. 2 illustrates one of the several forms of reproducing screens employed in the color television system of my invention; Fig. 3 is a diagrammatic illustration of the modulation control circuit of a radio transmitter embodying the principles of my invention; Fig. 4 is an elevational view showin an arrangement of scanning disc and co or screen movable step by ste according to the sweeping movement of t e scanning disc employed in the color television system of my invention; Fig. 5 diagrammatically illustrates the circuit arrangement for the multiple screens at the receiver; Fig. 6 illustrates a complete transmitter circuit embody,-

ing the modulation control circuit, the fragmentar trated-m Fig. 3; and Fig. 7 illustrates a. rece1v1ng circuit, a fragmentar portion of which has been illustrated in ig. 5.

The color television system of m invention makes use of the principles which have been set forth in detail in my Letters Pate nt No. 1,756,086, dated April 29, 1930, entitled Signaling system, and shown in my copending applications Serial No. 299,501, filed A r11 14,1928, entitled Glow discharge device, Serial No.- 414,957, filed December 18, 1929, entitled Television system and Ser. No. 434,777, filed Mar. 10, 1930, entitled Television transmission system. For a further understanding of the television system of my invention reference is made to my copending application Serial No. 460,760, iiled June 12, 1930, entitled Television sys In the color television system of my invention I employ scanning means adapted to sweep an object portion by portion in timed relation to a change in transmission frequency. I employ a step by step mechanism for moving a color screen into position intermediate each complete scanning operation cifedts of different color screens for the transmission of signaling energy modulated according to color effects produced by the object. At the receiver, I employ a multiplicity of color screens along which-a potential node moves according to the frequency of the received signaling energy, the screens being disposed in such relation one to another that they may be viewed through an epidiascope. The epidiascope has a multiplicity of screens disposed in parallel relation therein and each screen comprises a portion of which has been illuswhereby an object is scanned under the luminous disthose adapted to pass through a particular the movement of a .thus imparting the screens 1,2, 3

filter which is moved into position between the ob'ect and the scanning disc. .If the filter oes not pass any but red rays, the modulation of the transmitter is affected only by virtue of the amount of red in the picture or scene. Similarly, if the color filter pass'es green,'only the green in the pic-' ture or scene actuates the photoelectric cell adjacent the scanning disc during the neat revolution. There is a similar relation in the connection of the luminous discharge tubes at the receiver. That is, if the green filter at the transmitter follows the red filter at the transmitter, then the luminous dlS- charge tubes at the receiver are selected so that a red luminous first tube in the series and a discharge Similar co other color other color tubes at the receiver. In this way color d1scrimination is made at the'transmitter and television signals are emitted over a variable frequency range in successive periods of scanning, those colors in the picture which are passed by .the color filter being the only parts of the picture or scene which are transmitted during the individual scanning operations. Due to the ability of the optical system to sustain an image the color cciverwhich are rendered intermittently effectiveserve to display parts of the picture by potential node, the superimposed relationship of the several screens both depth and color to the reproduced image.

Referring to the drawings in more detail, Figure lillustrates the principle of my invention where reference characters 1, 2, 3 and A designate different luminous discharge tubes located at the television receiver in supereen luminous or relationships exist between the filters at the transmitter and the imposed relation with respect to a reflector b plate 5. The several screens-are subjected to illumination from-sources indicated at 6 and 7, the illuminating rays being directed upon and 4 as represented at 8 and 9 and reflected theref 10 through the optical system 11 and upon the reproducing screen 12. Fig. 2schematically shows the arrangement of the independent luminous discharge tubes in the separate or other gases havin dif-- the si naling 'nections taken to th discharge gas fills the as fills the next tu e in the series. b

screens or luminous dischar e screens at the re- AG rom as represented at Th cated at 14, 15, 16 and 17. Each of t e separate vessels or casings includes a luminous discharge element or inductance indicated at 18, 19, 20 and 21. These inductances may be connected in 22. heilluminating means 6 and 7 are directed upon the several dischar e tubes arranged as shown in the form 0 an e idiascope for directing an image througi the optical system 11 eral compartments of the gaseous discharge tube are independent one from the other and are each filled with gases having characteristic color roperties under conditions of luminous disc arge. The transmitter control circuit is shown in fragmentary form in Fig. 3 Where reference character 23 designates the inductance in the antenna circuit tuned by variable capacity 24, a portion of the inductance 25 is tapped as indicated at 26, and cone variable condenser system 27 where the stator plates are designated at 27a and the rotor plates at 27b. The driving motor 28 operates the set of rotor plates 27b to effect changes in frequency over a predetermined frequenoy range in accordance with the rotation of the scanning disc. A suitable reduction gear 28a is provided wherey a complete change in frequency over the transmitter frequency range occurs for every four revolutions of the scanning disc 29 which is driven by motor 28 and for every complete revolution of the color filter disc 30 which is also'drivenfrom motor 28. A suitable frame structure 31 has been illustrated for supporting the rotary shaft 32 of driving motor 28 on which there is mounted the scanning disc 29 and the actuatin disc 33. A frame structure 34 extends rom the frame structure 31 and rovides a bearing for the stub shaft 35 on w ich the color filter disc 30 is mounted. eneva gear mechanism interconnects shaft 35 with shaft 32 as indicated at 36. The radial slots in the Geneva gear 36 are adapted to receivethe pin 37 which is carried by disc 33 so that for each complete revolution of shaft 32, shaft 35 is advanced one-fourth of a turn imparting corresponding angular movement to the color filter disc 30. Screens of different color characteristics designated at 38, 39, 40 and 41 are carried by the color filter disc 30 insuch manner that each of the screens is successively moved into position etween the object 42 and the scanmng disc e scanning disc 29 has a s iral arrangement of apertures 44 therein aving a pitch adapted to sweep over a distance corresponding to the diameter of each color filter. e ends of the spiral row of apertures are spaced apart for a distance represented by t e angle a in Fig. 4 and during the time that the scanning disc is moving through the angle a movement is to the screen 12. The sevimparted to the color disc 30- series to the output circuit of receiving circuit designated. at

' terchange of color i l whereby a successive color filter is substituted for the preceding color filter utilized in the scanning of the object. That is to say, the color filter is stationary so lon as the light apertures 44 are'passing the fie d of any one o the color filters 38, 39, 40 or 41, but when the end of the light apertures 44 in the spiral motion is imparted to the nick infilters during the time that light is not passing through the scanning (1150 29. The photoelectric celd 43 is positioned behind the scanning disc 29 for receiving the light rays passing through the light apertures 44 for controlling the modulation circuit of the transmitter. Inasmuch as a complete frequency change in the transmitter circuit occurs.for each opr revolutions of sca ning disc 29, photoelectric cell 43 is activated, first, under the 'influence of one color screen through one-fourth of the frequency change, next, under the influence of the succeeding color filter through the next onequarter frequency change again under the action of the next succeeding color filter .during the next one-quarter frequency change, and finally underthe action of the succeedingcolor filter for the final one-fourth of the frequency change of the transmitted energy. I may employ additional color 'filters and further dividethe time period during which the transmitter is controlled under the action tion of the condenser of successive color filters. The object 42 is suitably illuminated by means indicated at for insuring the concentration of light through the color filter and upon the photoelectric cell 43 under control of the apertures 44 in scanning disc 29.

-In Fig. 5, I have illustrated one of the elements of the receiving system. The oscillator circuit including tube 46 is provided with a tuned circuit 47 for sustaining oscillations over the frequency range of the transmitted signaling energy. The inductances comprising the glow discharge tubes are shown at 18. 19, 20 and 21 each connected in series and also disposed in series with variable condenser 48 which is driven by motor 49 operating in synchronism with the rota 27 at the transmitter or at a speedwhich is one-fourth of the speed of the scanning disc 29 at the transmitter. For the purposeof more clearly showing the several inductances along which a potential node moves, I have shown these inductances spread in side by side relationship, but it will be understood that for the reproduction of images, these inductances are arranged in stacked or superimposed relations ip. a

In Fig. 6;1 have illustrated more clearly the transmitter circuit of my invention including a power amplifier designated at 50 and an oscillator designated at 51. The output of power. amplifier 50 connects to the tuned circuit comprising inductance 23 and condenser 24 which is in turn connected with the antenna-ground system illustrated at 58. The in at circuit of the oscillator is controlled y the photoelectric. cell 43. The condenser 27 connects to the taps 26 on inductance 23 for controlling the emitted frequenc of the transmitter in timed relation to t e o eration of the scanning'disc 29v and in time relation to the operation of the color filter disc 30 as heretofore described. The receiving system is illustrated in more dc tail in Fig. 7 wherein a receiving antenna is designated at 52 connected with the input circuit of radio frequency. amplifier 53 which is coupled with detector 54 and oscillator 55. The motor illustrated atr49 in Fig. 5 also drives the tuning controls 56 and 57 of the radio receiving circuit in timed relation to the operation of condenser 48.

It will be seen that the transmitter emits signaling energy over a variable frequency range, different portions of which are modulated according to the color effects which pass through selected color filters. At the receiverthe potential nodes along the luminous inductances occur in coordination with the modulation of the signaling energy at the transmitter. The potential node existout along a particular inductance is controlled according to the energy generated by the photoelectric cell 43 atthe transmitter for a given period of scanning under the influence of a particular color filter screen. That is to say, the color filter screens are accurately calibrated with respect to the several luminous discharge tubes at the receiver. Gases are selected for each of the luminous discharge tubes which will indicate the actual color of the object at the transmitter. For example, color screens 38, 39, 40 and 41 filter out those portions of the picture except the colors therein which will pass through the selected color screen. The luminous inductances 19, 20 and 21' at the receiver eac have corresponding color characteristics so that in the event that the object being reproduced may have certain dominating colors, those colors will be reproduced by the movement of potential nodes along the corresponding inductances. Care is taken to connect inductances of particular color characteristic in the same order as the color characteristics of the filter screens at the transmitter. For example, suppose luminous discharge tube 18 will reproduce red. and luminous dischar e tube 19 will reproduce green. 'lhe screen 38 will filter all but red rays at the transmitter, and the screen 41 will filter all but green rays. Inasmuch as the circuit at the transmitter is being maintained resonately responsive, any modulation which occurs during the interposition of a particular color screen between the object and the scanning disc will be reproduced at the receiver in thecorrespondingly colored luminous discharge tube. When the eifect of all of the luminous discharge tubes are viewed in superimposed relation, as illustrated in Fig. 2, the natural colors of the object at the transmitter may be accurately reproduced.

A brief summary of the operation of my invention is as follows: At the transmitter the rays of luminous energy corresponding to different portions of the picture are ob tained by means of the seaming member.

Difi'erent frequencies of the transmitted energy correspond to diiferept portions of the picture. At the receiver the incoming energy is distributed along a conductor which distribution changes with the frequency of the incoming energy and occupies positions along the conductor corresponding to the respective portions of the picture transmitted. The color screens at the transmitter are shifted in step by step progression for correspondingly controlling the glow discharge from the screens at the receiver in accordance with the movement of potential nodes along the screens. The control of condenser 48 or 27 in series with the screen is'such that the.

screen circuit is made resonately responsive to different frequencies over the entire fr quency range of the system.

For the purpose of explaining my invention, I have illustrated my system of color television in association with an antennaground circuit for the transmission of energy through space, but it will be understood that the prmciples of my invention are e ually applicable to wiredradio -systems w ere high frequency currents are conveyed by l1ne wires from a transmitting station to any number of interconnected receiving stations.

While I have described my invention in a preferred embodiment, I desire that it be understood that modifications may be made and that no limitations 'on my invention are intended other than are imposed by the scope of the-appended claims.

What I claim as new and desire to secure by Letters Patent of the United States is as follows:-

1. In a television system, a. transm tter comprising means for transmitting signaling energy over a periodically recurring band of frequencies, means for scanning an obJect, means for shifting a color filter in the path of said scanning means and the object to be scanned in successive step by step movements, said color filter shifting means operating in timed relation to the periodic frequency change of said transmitter,-and luminously responsive means at a receiver for reproducing the color effects under control of changes in frequency at said transmitter and in predetermined relation to the successive operations of each of the color mitter.

2. In a television system, means for trans filters at the transmittin television signaling energy over a periodica dy recurring frequency and, means for me ulating the transmitted energy, a multiplicity of color screens shiftable in step by step movement into the path of the inodulating means and the object to be scanned, means for scanning the object under the influence of each of said color filters throughout a portion of the transmitted frequency band, and receiving means including a multiplicity of glow discharge color filters each luminously responsive to a varying potential node under control of frequency changes at the transmitter.

3. In a television signaling system, means for periodically transmitting signaling energy over a variable band of frequencies, means for scanning an object and variably controlling the transmission ergy by the effects thereof, a multiplicity of color filters shiftable in step .by step move ment to a position between the object to be scanned and the scanning means, means coordinating the movement of said color filter with the operation of said scanning means and the periodic change in frequency of the transmitter, and receiving meansincluding a plurality of luminously responsive screens connected in series and each having a glow discharge color characteristic corresponding to the color ,characteristic of-a particular color filter at the transmitter for the visual reproduction of signaling energy in the form of a moving potential node according to frequenc changes at the transmitter. 4. 1 a television system, rotatable drivmg means, a rotatable shaft driven by said drlving means, a scanning disc driven by said rotatable shaft, an auxiliary disc carried by said rotatable shaft/an auxiliary shaft extending parallel to the aforesaid shaft, a ro-' tatable carrier mounted on said auxiliary shaft, a multiplicity of color screens having characteristics according to different colors of the spectrum mounted on said rotatable carrier, a Geneva gear on said auxiliary shaft, and means on said auxiliary disc adapted to engage said Geneva gear for imparting angular movement to said rotatable carrier for each complete scanning operation of said scanning disc.

5. In a television system, a driving motor, a rotatable shaft driven by said motor, a scanning disc carried by said shaft, an auxiliary member carried by said shaft in spaced relation to said scanning disc, an auxiliary rotatable shaft extending parallel to the aforesaid shaft, a rotatable carrier on said auxiliary rotatable shaft, color screens carried by said auxiliary rotatable shaft and having characteristics according to different colors of the spectrum and aGeneva gear carried by said auxiliary rotatable shaft and projectable into the path of the member carried by said first mentioned rotatable shaft I forefiecting angular displacement of said rotatable carrier for each complete scanning operation of said scanning disc. I

6. Television apparatus comprisin a drivi mechanism, a rotatable shaft driven by sai driving mechanism, a scanningdisc carried by said shaft, said scanning disc havmg a row of s irall disposed apertures therein terminatmg s ort of a predeter-' mined solid angle on said-scanning dis o, an

auxiliary diametrically extending membercarried said shaft in spaced relation to said scanning disc, an auxiliary rotatable shaft extending parallel to the aforesaid ro-,

tatable shaft, a rotatable barrier on said auxiliary rotatable shaft, separate color screens on said rotatable carrier, a Geneva gear on said auxiliary rotatable shaft engaging with the diametrically extending member on said first mentioned rotatable shaft, said gear being timed in operation for angularl shifting said rotatable carrier during the time interval that the solid angular portion of said scanning disc passes the observing position of the television apparatus, while presenting successive color screens in the observing position of said apparatus across the field traversed by the apertures in said scanning disc for performing each successive scanning operatlon. k

7. In a televisionsystem,rotatable driving means, a rotatable shaft driven by said driving means a scanning disc driven by said rotatable shaft, an auxiliarvdisc carried by said rotatable shaft an auxiliary shaft extending parallel to the aforesaid shaft, a rotatable carrier mounted on said auxiliary shaft, a multiplicity of color screens having characteristics according to different colors .of the spectrum mounted on said rotatable carriem and means on said auxiliary disc for im artin angular movement to said rotatab e carrler for each complete scanning operation of said scanning disc.

In testimony whereof I afiix my signature. I

CHESTER L. DAVIS. 

